This invention relates to a centrifugal clutch, and more particularly to a centrifugal clutch which is substantially free from slippage between clutch engaging members at engagement as well as at disengagement.
A conventional centrifugal clutch for use in transmissions or like devices is comprised of an input member, an output member, and a pair of engaging members connected, respectively, to the input member and the output member, and disposed for frictional engagement with each other to couple the input member and the output member together. One of the engaging members if formed integrally with a centrifugal weight so that the frictionally engaging force of the engaging members, i.e. the coupling force of the clutch varies in response to centrifugal force produced in the centrifugal weight. That is, the coupling force of the clutch varies in a continuous manner in response to changes in the centrifugal force of the centrifugal weight. As a consequence, when a load is applied on the clutch, there can occur a slip between the two engaging members while the coupling force has a value falling within a range between zero and a value slightly smaller than a value required by the load. Further, as the load increases, the clutch is required to have its coupling force increased to cope with the increased load, so that the range of values of the coupling force of the clutch within which the above slip can occur becomes wider. Such slip can occur both at engagement of the clutch and at disengagement of same. Moreover, engagement and disengagement of the clutch can mostly occur almost at the same rotational speed. Consequently, when the centrifugal force of the centrifugal weight varies about a value thereof which makes the coupling force of the clutch zero, there can occur fluttering or repeated alternate engagement and disengagement of the engaging members. If the clutch is held in an coupling force region where slips can occur in the engaging members, for a long period of time, or if it is used in a condition where such fluttering can frequently take place, it can result in a shortened effective life of the clutch.